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Homework Help: Question on Energy

  1. Apr 10, 2006 #1
    My teacher assigned a few problems, and I'm having difficulty with one of them. The question is:

    In order to accelerate a 2 kg car from rest to a speed of 16 m/s, 400 J of work are done by the motor of the car. The acceleration takes 10s. Calculate:

    a) the distance moved by the the car (I got 80 m)
    b) its acceleration (1.6 m/s2)
    c) the force provided by the motor
    d) the frictional force opposing the car's motion
    e) the work done to overcome friction
    f) the final kinetic energy of the car

    I need help especially with c and d. Thanks.
  2. jcsd
  3. Apr 10, 2006 #2
    c) W=fd
  4. Apr 11, 2006 #3


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    Gold Member

    d) find the work that was done on the car to get to 16m/s^2, it should be less than 400J, the difference is the work done by friction. Since the force is constant, just divide that work by the distance to get the force.
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